1. Field of the Invention
The present invention is broadly concerned with new agriculturally useful compositions comprising anhydrous ammonia supplemented with one or more types of agricultural actives. More particularly, the invention is concerned with such compositions, and methods of preparing and using the compositions. In general, the products include respective quantities of anhydrous ammonia, ammonia solution, and one or more agricultural actives.
2. Description of the Prior Art
Anhydrous ammonia is widely used as a fertilizer. This material is gaseous at normal ambient temperatures, and therefore is maintained under pressure in tanks to keep it in a liquid form prior to application. Anhydrous ammonia is typically injected from a pressure tank into the soil below grade in order to inhibit the volatilization of the ammonia into the atmosphere. Although anhydrous ammonia has no pH owing to the fact that it is water-free, it is an extremely caustic material which must be handled with great care. For example, if water is injected into anhydrous ammonia, the result is a violent and uncontrolled exothermic reaction. Although not generally practiced, it has been known to mix fertilizer components with anhydrous ammonia prior to application thereof to the soil. See, e.g., U.S. Pat. No. 3,997,319, which describes the addition of zinc acetate to anhydrous ammonia to form a mixed fertilizer.
In recent years a series of U.S. patents have issued describing biodegradable polymers having significant agricultural facilities, particularly when used in combination with conventional fertilizers or pesticides. For example, U.S. Pat. No. 6,515,090 describes dicarboxylic copolymers made up, e.g., of moieties of itaconic acid and maleic anhydride. This patent also discloses that such copolymers may be partially neutralized with metal or other cations, and can be used to form composite products with fertilizers. These combined fertilizer-copolymer products have been shown to increase the availability of phosphorous and other nutrients for uptake by growing plants, and can be applied to soil adjacent the plants or in foliar applications. Moreover, these copolymers can be used to good effect in combination with various pesticides, as described in U.S. Pat. No. 7,655,597. Polymers in accordance with the '090 and '597 patents are commercially available from Specialty Fertilizer Products, LLC of Leawood, Kans. under the designations NUTRISPHERE-N® and AVAIL®. NUTRISPHERE-N® is a 40% by weight solids aqueous copolymer of substantially equimolar amounts of itaconic and maleic anhydride moieties partially neutralized with calcium ion (CAS#877469-38-0) and having a pH of 2.5-5. AVAIL® is a 40% by weight solids aqueous copolymer of substantially equimolar amounts of itaconic and maleic anhydride moieties partially neutralized with sodium ion (CAS#556055-76-6) and having a pH of 6-8.
As indicated, these synthetic polymers are provided as aqueous mixtures containing approximately 40% by weight polymer. Therefore, these aqueous polymer mixtures are not suitable for direct injection into anhydrous ammonia even though, from a plant nutrition standpoint, such mixtures would be highly useful.
Similarly, other types of solid or liquid agriculturally useful ingredients could be advantageously mixed with anhydrous ammonia, except for the tendency of solids to segregate from anhydrous ammonia, and/or because of the presence of water.
There is accordingly a need in the art for new agriculturally useful compositions and methods permitting actives such valuable fertilizers to be incorporated into anhydrous ammonia without experiencing the aforementioned problems.